This invention relates to compact reciprocating pumps, and more particularly it is concerned with an electromagnetic pump of the reciprocating type.
In the field of reciprocating pumps, it has hitherto been customary to use a device in the form of a pressure accumulator which comprises a resilient means and a diaphragm, or a hollow sack-shaped resilient member in which gas is sealed, in order to minimize the magnitude of pulsations of the liquid delivered by the pumps so that the pumps may deliver the fluid at a constant pressure and in a constant volume at all times. Also, relief valves have hitherto been in use for keeping the delivery pressure of the pumps constant at all times. In one type of such relief valves, a valve body is brought into pressing engagement with a valve seat formed in a leak port by means of a spring or other resilient means so as to close the leak port. If the delivery pressure of the pump rises and exceeds a predetermined level, then the delivery pressure of the pump overcomes the biasing force of the spring, with a result that the valve body is brought out of engagement with the valve seat and the leak port is opened. Thus a quantity of liquid representing the excess pressure is spilled off from the outlet side of the pump to keep the delivery pressure of the pump constant at all times. It is known to combine the aforementioned two separate features from the prior art into a single device where each feature performs its normal function in the combination and no unobvious results are obtained by the combination.